Near-infrared spectral region

One further example of this principle of bridging the aryl groups of a triarylmethane phthalide was reported in 1986.108 Thus, treatment of phthalide 27 with aluminum chloride results in the formation of the spirobenzanthracene 28 as shown in Scheme 11. These color formers also exhibit absorption in the near infrared spectral region, but no further reports of such compounds have since been published. 

What near-infrared spectral region will be targeted for the calibration development, for example, combination region, first combination/overtone, or second combination/overtone Each region will imply a different transmission path length, and hence cell or probe design. 

The visible to near-infrared spectral region (375-740 or 680-1080 nm, resolution < 10 nm) is the domain of a micro spectrometer presented by the Institut fur Mikrotechnik Mainz [121]. This device (overall dimensions 16 x 28 x 38 mm) is commercially available but not yet adapted to direct inline measurements in a plant (Figure 4.72). 

Water solubilized by RMs in hydrocarbon solvents by different surfactants (anionic, cationic and zwitterionic) exhibits two absorption bands in the near infrared spectral region (5200-4700 cm 1) due to water populations (Sunamoto et al., 1980), one assigned to the surfactant polar heads and the other to water dispersed in the bulk phase. Three methods have been proposed to evaluate the acidity in the water pool of soft-core of reverse micelles ... 

Absorption bands in the near infrared spectral region (700 to 3000 nm) are the result of overtones or combinations of fundamental modes of vibration in the mid-infrared range (4000 to 600 cm1). Correlation charts are available that show where certain functional groups can be expected to give absorption in the near-infrared spectral region. 

High transparency in the visible and near infrared spectral region... 

Absorption and reflection in the near infrared spectral region have been employed to study the fundamental bandgap, phonons and the free carrier absorption in wurtzite InN films [1-7], Raman spectroscopy has been used to identify the phonon modes [8,9]. 

Class 0. Sources with a very faint protostar in the optical and near-infrared spectral region, but with considerable luminosity in the submillimeter spectral region. During this phase the molecular cloud material starts to collapse and to build up a stellar embryo and its associated disk. 

Chemiluminescence (CL) is the emission of light, usually in the visible or near infrared spectral region, as a result of an excited electronic molecular state, formed in a chemical reaction, returning to the ground state. Bioluminescence (BL) is the same emission process but involves a biochemical process such as an enzyme-mediated reaction for excitation. Chemiluminescence is a relatively rare phenomenon because... 

Primary length measurements are these days based on optical frequency standards. If one needs a unit of length, for example, a wave-length for interferometric measurement, then one divides the optical frequency by the value of the speed of light (299 792 458 m.s ) as defined in the SI metre. The mise en pratique of the metre [44] lists a number of frequency-stabilised lasers at various wavelengths in the visible and near infrared spectral regions. 

A-3 of the Appendix lists the numerical data. In the visible and near-infrared spectral regions the fluxes were mainly derived from ground-based measurements at mountain stations supplemented by aircraft and balloons as platforms. The ultraviolet portion of the solar spectrum has been explored with instruments on board rocket sondes and satellites. These data are of special interest here. Measurements before 1980 have been reviewed by Ackerman (1971), Simon (1978), and Nicolet (1981). More recent data have been reported by Mount and Rottman (1981,1983,1985) and Mentall etal. (1985). 

Table 1. Typical absorption and scattering coefficients of tissues in the red/near-infrared spectral region (600-800 nm) and resulting approximate effective attenuation coefficient and penetration depth. Note that for any tissue type, there is considerable patient-to-patient and, for tumors, lesion-to-lesion variation in these properties...

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